Overall performance design and matching of a new static shaft and rotating casing small turbofan engine

Traditional small aircraft engines have problems of difficult thrust-to-weight ratio improvement and high manufacturing cost, significantly limiting performance enhancement and application expansion of small aircraft. Developing high-performance engines is critical for aviation advancement. This study addresses this issue by proposing a novel titanium-alloy 3D-printed “static shaft and rotating casing small turbofan engine”. The structure and working principle of this new concept are analyzed, the overall design calculation method is developed for the first time, the combustor thermodynamic cycle method is established, and the component matching relationships are investigated. The results show that the compact structural layout is achieved via the parallel configuration of segmented compression and combustion, breaking the traditional idea of increasing turbine inlet temperature for thrust augmentation. This forms a design paradigm where the turbine mainly provides mechanical power and the rear combustion chamber supplements thrust. The designed engine has a total pressure ratio of 9.84, achieving a high thrust of 4813.67 N, a thrust-to-weight ratio of 5.35, and a specific fuel consumption (SFC) of 0.94 kg/(kN·h). Compared to existing small aircraft engines, it demonstrates a 13.83 % higher thrust-to-weight ratio at similar SFC, an 18.26 % lower SFC at comparable thrust-to-weight ratios, and a 35.71 % weight reduction under the same thrust. The dual combustor layout expands the Brayton cycle area. In conclusion, the novel engine has the potential to become an efficient power source for future small aircraft. The key innovation lies in combining titanium-alloy 3D-printed with a unique static shaft and rotating casing structure, overcoming traditional design limitations. It surpasses previous studies in overall performance, offering a new direction for small aircraft engine design and performance improvement, and is expected to drive technological innovation in the small aviation field.